This Android version (4.1) was announced at Google's IO conference on July 27th, 2012. It included major updates such as:
Google Butter
- feature improvements with respect to the display
- screen refresh moved to 60htz
- GPU and CPU cycles optimized
Google Now
- monitors actions such as searches and travel to give personalized information, organized into cards
Notification Updates
- one can now enable/disable notifications per application
- options, such as snoozing appointments and returning calls, can be chosen from notifications themselves
- support for additional information (news headlines, etc.) display within notifications
